Mishima M, Balassy Z, Bates J H
Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.
J Appl Physiol (1985). 1994 Nov;77(5):2140-8. doi: 10.1152/jappl.1994.77.5.2140.
We measured the time course of alveolar input impedance using two alveolar capsule oscillators after intravenous bolus administration of 20 mg of histamine in open-chest dogs. Impedances (24-200 Hz) were obtained every 2 s after an injection for 100 s. Each impedance was fit with a model consisting of a pathway (with resistance and inertance) leading from the alveolar capsule into a subpleural region (with elastance EA) that, in turn, was connected to the lung compartment (consisting of the remainder of the lung and positive end expiratory pressure system) via another pathway (with resistance RA). In all cases (6 dogs, 2 capsules each), the resistance and inertance leading from the alveolar capsules were negligible. The correlation of the relative increases in RA obtained from the two capsule oscillators in each dog was not significant. The correlation for EA also was not significant. The times at which RA achieved values of 20% greater than baseline were not significantly correlated between the two capsules, as was the case for EA. However, the baseline values of EA and RA from a given capsule were significantly correlated, as were their fractional increases with histamine. These results show that both the magnitude and timing of changes in local lung resistance and elastance are spatially extremely heterogeneous.
在开胸犬静脉注射20毫克组胺后，我们使用两个肺泡囊振荡器测量了肺泡输入阻抗的时间进程。注射后每2秒获取一次100秒内的阻抗值（24 - 200赫兹）。每个阻抗值都与一个模型拟合，该模型由一条从肺泡囊通向胸膜下区域（弹性为EA）的通路（具有阻力和惯性）组成，胸膜下区域又通过另一条通路（具有阻力RA）连接到肺腔室（由肺的其余部分和呼气末正压系统组成）。在所有情况下（6只犬，每只犬两个囊），从肺泡囊引出的阻力和惯性可忽略不计。每只犬从两个囊振荡器获得的RA相对增加量之间的相关性不显著。EA的相关性也不显著。两个囊之间，RA达到比基线值高20%时的时间没有显著相关性，EA也是如此。然而，给定囊的EA和RA基线值显著相关，它们随组胺的分数增加也显著相关。这些结果表明，局部肺阻力和弹性变化的幅度和时间在空间上极具异质性。
